Point 7 Intro Pathway Deficit Note Summary Overview Problems Contents Anatomy

Point: 7. Hypoglossal Nucleus Function: Motor control of IPSI. tongue muscles. Pathway: Axons of neurons in the hypoglossal nucleus pass ventrally to exit brainstem between the pyramid and the inferior olive. Deficits: Lesion of the hypoglossal nucleus or nerve results in atrophy of the IPSI. tongue muscles and deviation of the tongue to the IPSI. (weak) side upon tongue protrusion. Lesion of the corticobulbar fibers to the hypoglossal nucleus results in CONTRA. deviation of the tongue upon protrusion (NO ATROPHY). Other Note: CORTICOBULBAR PROJECTIONS TO THE HYPOGOSSAL NUCLEUS ARE CROSSED (so sorry!) LESION OF CORTICOBULBAR FIBERS IS CALLED A SUPRANUCLEAR LESION (rostral to the nucleus).